CHAPTER TWO — THE GUEST UPSTAIRS
Four days earlier, Ethan would never have imagined Carol near his pool with anything worse than a complaint about noise.
She had lived next door for nineteen years and had opinions about everything from fence height to holiday decorations.
She also maintained the neatest front garden on the block and collected discarded bicycles for the local repair club.
Ethan knew both versions of her, though he preferred conversations that ended before she began counting his guests.
He was thirty-six, a science teacher between school contracts, and his late father had left him the house and its enormous, expensive swimming pool.
For most of the year, he used the garage as a workshop for neighborhood students who liked building small machines.
Their latest fascination was underwater robotics.
An organization called Blue Current had offered to provide kits and mentors for a regional competition.
Ethan had volunteered his pool for the trials because the public aquatic center had closed for repairs.
The idea had seemed harmless, even generous.
Teenagers would build small remote-controlled machines, guide them through underwater hoops, and retrieve colored markers from the pool floor.
Saturday’s event would feature eight teams, a local news photographer, and a modest scholarship for the winners.
The organizer, Oliver Venn, had arrived early with two crates of equipment and a promise that insurance covered everything.
Oliver was friendly, decisive, and aggressively grateful.
He had offered to stay in a motel, but Ethan had put him in the guest room to simplify the preparations.
By the second night, the cheerful organizer had taken over the garage and begun locking his equipment crates.
He called them proprietary training units.
Ethan disliked the locks but accepted the explanation because schools often worried about children copying designs before competitions.
On Tuesday morning, a freshman named Priya had brought in a yellow-and-black underwater robot she built with her friend Mateo.
Oliver handled it for a long time and complimented the workmanship.
Then he set it beside one of his orange prototype vehicles.
“These are fun,” Oliver said, “but ours can do something more interesting than retrieve rings.”
“What?” Priya asked.
“Work autonomously.”
Priya frowned.
“Underwater, without someone driving?”
Oliver smiled.
“You’ll see Saturday.”
Later that afternoon, Ethan spotted Carol outside the fence listening to the kids test a motor.
“They’re loud,” she said.
“They’re fourteen,” Ethan replied.
“One of those boys in your garage is fourteen?”
“Some are sixteen.”
“Are they being paid?”
“They’re competing for a scholarship.”
“Who owns what they invent?”
The question seemed so unlike her usual complaints that Ethan laughed.
Carol did not.
“Read the fine print,” she said.
He promised he would, then forgot because Mateo’s controller had started smoking and required attention.
On Wednesday morning, Ethan noticed the orange piece under the drain cover.
He was cleaning leaves when he saw it lodged between two bars.
He photographed it because it had a distinctive three-pronged shape.
He intended to show the picture to Oliver.
But Oliver was on a video call upstairs, speaking sharply enough that Ethan heard him through the hallway.
“We need the last one accounted for,” Oliver said.
“I don’t care what the parents think they signed.”
Ethan stepped away before hearing anything else.
He told himself he had probably misunderstood a discussion about equipment inventory.
By Friday noon, that explanation no longer satisfied him.
Especially after Carol dumped an entire bucket of brown garden sludge into the pool.
